Tuesday, July 16, 2013

As Boozer Emerson asked me at the bar…“Does that Baseball-Referral place use it?”

To the casual baseball fan, there isn’t a tidy Bo Derek-y stat (10!) to rate the greatness of, say, Bo or Derek.

Guys are gaged by a gumbo of mumbo-jumbo, confusing stats that, only when cooked together, lead us to unequivocal evaluations such as “He’s pretty good,” or “He’s, like, really good.”

Sure, you’ve heard of WAR, last season’s buzz acronym (BA) during the American League MVP debate. But on this day, I’m here to introduce you to (arguably) the most Bo Derek-y stat out there, a stat that could change the way you look at stars — and also help you appreciate the greatness of Carlos Eduardo Gonzalez.

Denver, meet wRC+.

It stands for weighted runs created plus, a stat Grantland.com baseball writer and Denver resident Jonah Keri calls the most telling offensive stat in the game. As for the Rockies’ Cargs — yes, I call CarGo “Cargs,” which I believe is the first-ever nickname of a nickname — the outfielder is fifth in the National League (153). He, of course, will start in Tuesday’s All-Star Game.

So, what is this thing?

In a sentence, it’s a stat that dissects a player’s overall offense, while adjusting for the effects of the parks and league he plays in. It’s a pretty cool way of looking at the grand old game.

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Take the average player with RAA of zero and average RAA "relative per out" is of course approximately .3 although this seemed to be news to Tango. (I'm using ~ as approximately equal) .3*PA is ... wait for it ... Rrep (give or take). RAA "relative per out" is RAR.

The squiggle factor I think is just trying to get rid of (lgOBP - .3) and the difference between PA and the rest (although I assume IBB, RoE, etc. are in the full calculation).

It's all just going around in circles to get back where they started. You've got your estimate of runs, you know the number of PAs and you have estimates of average (and replacement) runs for a given number of PAs. Nothing is "based on wOBA" because wOBA is just a rescaling of estimated runs, PAs and league average. wRAA and wRC+ are just "unscaling" wOBA back into quantities you already have and then, in the case of wRC+, rescaling again.

I don't necessarily have a problem with rescaling if you think it helps comprehension but they should have realized that RAA "relative per out" was RAR. They should have known that RAR/PA would come out to a mean of .3 -- they designed it to do so! They should have known that wOBA*PA just basically takes them back where they started.

Upshot ... if you want a rate stat, RAA/PA (or RAR/PA per your preference) is all you need. The others are just variations on that.